A recent study published in the journal Nature Medicine has shed new light on the genetic underpinnings of Alzheimer’s disease, suggesting that it may have a stronger inherited component than previously known. The study highlights the role of a gene linked to the common form of dementia, known as apolipoprotein E (APOE), in increasing the risk of developing Alzheimer’s.
Traditionally, Alzheimer’s has been categorized into familial and sporadic forms, with familial cases being rare and caused by mutations in specific genes. However, the new research suggests that a significant portion of Alzheimer’s cases, approximately 1 in 6, may be considered inherited due to variations in the APOE gene.
The study focused on the APOE4 gene variant, which has long been associated with an elevated risk of Alzheimer’s disease. Individuals carrying two copies of the APOE4 gene were found to be almost certain to develop the biological changes associated with Alzheimer’s, such as the accumulation of beta amyloid plaques in the brain.
Researchers compared individuals with two copies of the APOE4 gene to those with other genetic forms of Alzheimer’s and found that the progression of the disease and the severity of symptoms were remarkably similar across different genetic variants. Individuals with two copies of APOE4 tended to develop Alzheimer’s approximately 10 years earlier than those with other gene variants.
While having two copies of the APOE4 gene significantly increases the risk of developing Alzheimer’s, not all individuals with this genetic profile experience cognitive decline. Some individuals may have high levels of beta amyloid in their brains but remain asymptomatic, possibly due to other genetic or environmental factors that offer protection.
The study underscores the importance of understanding the genetic basis of Alzheimer’s disease and suggests that APOE4 should be considered a genetic form of the disease rather than just a risk factor. Further research is needed to explore the implications of these findings for Alzheimer’s diagnosis and treatment.
